1. Field of the Invention
The invention relates to an apparatus for preventing self-injurious behavior in patients. More particularly, the invention teaches an improved apparatus for sensing self-injurious behavior and for transmitting a signal to a separate stimulation module which then supplies aversive electrical stimulation to the patient's skin.
2. Description of the Prior Art
The use of aversive stimulation to prevent certain types of behavior is known in the art. U.S. Pat. No. 3,998,209, issued to Gilbert Macvaugh on Dec. 21, 1976, teaches the application of electric shock pulses, generated by a charged capacitor circuit, for deconditioning snoring. U.S. Pat. No. 3,885,576, issued to Elliott Symmes, on May 27, 1975, teaches the use of electric shock as a means to deter smoking. In that patent a mercury switch is mounted on a wristband so that when the user moves his arm (e.g., to place a cigarette to his lips), the mercury switch closes and allows an electric current to flow to electrodes mounted on the user's wristband.
The use of aversive stimulation to inhibit self-injurious behavior was first described by Mooza Grant in U.S. Pat. No. 3,834,379, issued Sept. 10, 1974. Mooza Grant describes an apparatus which conditions psychotic self-destructive patients against self-injurious blows to the head. The apparatus contains a helmet which is mounted on the patient's head to absorb self-injurious blows. The helmet contains a metallic cylinder and a movable pin disposed centrally therein. When the patient strikes the helmet, the pin contacts with the cylinder and establishes an electrical contact which activates an electronic package (described as being disposed within a packet in patient's clothes.) An electrical pulse generated in the electronic package is sent to the electrodes contained in an arm band and provides an aversive electric shock to the patient's arm. The helmet, electronic package, and stimulation electrodes are all connected by electrical wires.